Color display devices are well known and are used in, for example, televisions, monitors, laptop computers, mobile phones, personal digital assistants (PDA's) and electronic books.
A wide color gamut color display device is described in WO2004/032523 of same applicant, which herewith is incorporated by reference. The color display device displays a color image with a wide color gamut and is provided with a plurality of picture elements, two selectable light sources having different predetermined radiance spectra, color selection means which in combination with the selectable light sources are able to produce respective first and second primary colors on the display panel and control means arranged to select alternately one of the selectable light sources and to provide a portion of the picture elements with image information corresponding to the respective primary colors obtainable with the selected light source. The primary colors of the display device can be selected in a time sequential and space sequential way which enable a reduction of a color break-up.
The device is of the type that is also called Spectrum Sequential Display and is an in-between form of a regular, for instance an RGB, display and a color sequential display, which also is called Field Sequential Display. The display primaries are formed spatio-temporally, using both multiple color filters, and multiple (spectral) light sources, which are alternately flashed in a number of sub-frames.
The color gamut of such a display is very much larger than what can be realized with a conventional display and conventional 3-phosphor mix fluorescent lamp, while it gives comparable brightness.
In an ideal Spectrum Sequential Display, as disclosed in WO2004/032523, there is theoretically no interaction between two sub-frames. However, in a real life Spectrum Sequential Display, electro-optical cross talk occurs. This is caused by a number of effects, such as:    1. The slow temporal electro-optical LC response of the LCD panel. The abbreviation LC stands for Liquid Crystal, the abbreviation LCD for Liquid Crystal Display.    2. The temporal lamp profile, which in turn is determined by:    a. The phosphor decay time of the individual phosphors;    b. The spatio-temporal optical cross talk in the backlight if operated in lamp scanning mode; and    c. The specific lamp timing, relative to the display addressing.
This electro-optical cross talk causes that the display primaries are not as saturated as intended. It in turn causes a shift in the intended color. This may be particularly annoying in a multi-primary display, where freedom in the six primaries allows for different combinations of drive values to result in the same, uniform, intended color. Under influence of the cross talk, these different drive levels can result in differing shifts in color, which results in very visible and annoying contouring and noise artifacts.
In addition, this cross talk also increases in severity for higher frame rates, which are essential for proper operation of Spectrum Sequential Displays that are not allowed to have visible flicker. For instance for a 60 Hz Spectrum Sequential television set (TV), a 120 Hz sub-frame rate has to be applied when using two sub-frames, and for a 50 Hz TV it is desired to apply a 150 Hz sub-frame rate, possibly aided by an up-conversion to a 75 Hz frame-rate to ensure a flicker-less Spectrum Sequential TV.
The temporal waveform of the lamp response of a Spectrum Sequential Display is also a cause for electro-optical cross talk.
This cross talk could be reduced, albeit eliminated, when we apply:    1. A very fast LC response panel (OCB or the like)    2. A flashing lamp scheme, rather than scanning, which also implies fast addressing and settling of LC.    3. Very fast response phosphors, or LED/laser based light sources.
However, these measures add considerable cost and complexity to the Spectrum Sequential Display system, and incur reduced efficiency. Therefore, it is contemplated that, at least for the time being, there will always be a cross talk component in a commercially viable Spectrum Sequential Display.
Hence, it is desired to provide an advantageous way of reducing electro-optical cross talk in a wide gamut Spectrum Sequential Display, allowing for increased flexibility, and cost-effectiveness without substantially increasing power consumption of the display, while still maintaining comparable brightness levels.